[Multicenter study of the sensitivity to beta-lactam antibiotics of 1,707 strains of Pseudomonas aeruginosa isolated at a general hospital].

1,707 non replicate clinical strains of Pseudomonas aeruginosa from non teaching hospitals were investigated. Beta-lactam antibiotics were tested by agar disk diffusion method. Variance analysis revealed a significant interaction between strains and experimental laboratories. The bacterial population was grouped according to the diameters of inhibition zones of antibiogram, into five phenotypes. Pseudomonas aeruginosa is frequently isolated from urines and pulmonary sampling, rarely from blood cultures. Resistance to beta-lactams increased significantly with the duration of hospitalisation, and age of patients. Clinical strains are significantly more resistant in blood cultures, and for strains isolated from reanimation. 84% of strains are susceptible to ticarcillin.